Had a look around the interwebs,Gigabyte say their SC15 KL GSync laptop with a 120HZ screen will be released around June.
TBH,if you already have a laptop with a GTX1070,I would probably get a GSync display and use that instead. A 24" 144HZ one is around £250 to £300
IIRC. Not sure if these KL ones are anything other than a sidegrade especially when you consider laptops are easier to implement GSync and FreeSync in the first place.
Plus either way,a £2000 laptop with no upgradeable graphics seems a waste to me,as GTX1070 performance will probably be midrange in 2018.